1.
place a Layer or FlexBoxContainer with a Bulleted List, properties: enable responsive fonts, font-size 10.
2.
set a breakpoint 320px.
3.
inside breakpoint change Bulleted List font-size to 8 and fill the items with some text.

--> the height of the Bulleted List inside breakpoint is not calculated correctly.
The same error also within Tables.
Wysiwyg Web Builder Version 12.3.0 (Dec 15 2017).